Khewra Salt Mine...!!!

Khewra Salt Mine
The Khewra Salt Mine (or Mayo Salt Mine) is located in Khewra, north of Pind Dadan Khan, an administrative subdivision of Jhelum District, Punjab Region, Pakistan, which rises from the Indo-Gangetic Plain. ... Estimates of the reserves of salt in the mine vary from 82 million tons to 600 million tons.

The salt reserves at Khewra were discovered when Alexander(Sikandar-e-Aazam) the Great crossed the Jhelum and Mianwali region during his Indian campaign. The mine was discovered, however, not by Alexander, nor by his allies, but by his army's horses, when they were found licking the stones.[14] Ailing horses of his army also recovered after licking the rock salt stones.[15] During the Mughal era the salt was traded in various markets, as far away as Central Asia.[16] On the downfall of the Mughal empire, the mine was taken over by Sikhs. Hari Singh Nalwa, the Sikh Commander-in-Chief, shared the management of the Salt Range with Gulab Singh, the Raja of Jammu. The former controlled the Warcha mine, while the latter held Khewra. The salt quarried during Sikh rule was both eaten and used as a source of revenue.